West Nile virus in North America: perspectives on epidemiology and intervention

West Nile virus (WNV) invaded New York in 1999 and rapidly swept across the North American continent to the West Coast, north into southern Canada and south into Latin America, with minimal genetic change. Regional epidemics in equines and humans typically have included a year of viral introduction with minimal activity, successful overwintering, explosive amplification to epidemic levels the following year and then rapid subsidence. Overwintering possibly included long-term mosquito or avian infections, continued low-level transmission at southern latitudes and dispersal by south-north migrants. Explosive amplification has been associated with infections in several corvid species and other urban birds that produce elevated viremias capable of efficiently infecting even moderately susceptible mosquito species. Intervention has included mass vaccination of equines, and proactive and reactive mosquito control. Proactive mosquito control in areas with established infrastructure has been successful in reducing case incidence.     

Morphological and Physiological Responses of Plantain (Plantago lanceolata) and Chicory (Cichorium intybus) to Water Stress and Defoliation Frequency

Plants are often subjected to periods of water stress. There are little data examining the effect of water stress on the forage species Plantago lanceolata and Cichorium intybus. In two pot experiments with P. lanceolata and C. intybus, morphological responses under optimum, dry, and very‐dry water treatments with weekly, fortnightly and 3‐weekly defoliation intervals and physiological responses under optimum and very‐dry water treatments were measured. A third experiment compared the rooting depths of P. lanceolata and C. intybus under field conditions. These findings suggest that both P. lanceolata and C. intybus can survive and continue to grow under water stress conditions with the main differences between the two species being attributable to morphological characteristics (root mass, taproot diameter and shoot mass fraction) rather than differences at a physiological level. Overall, the results suggest plantain may be more productive under moderate drought due to its greater shoot mass fraction, whereas chicory may be more productive and persistent under severe drought due to its greater root mass, taproot diameter and root depth under field conditions.     

A Community Forestry Model Linking Research,Management, Education,and Stakeholder Engagement: Case Study Results from the Town of Weston,Massachusetts, USA

Forested land in the eastern United States is owned by a complex mix of public and private owners, often with highly varied objectives and uses. There is an increasing trend at local scales of community forestry programs that use community-based decision making to determine what type of management will occur on town-owned forests. Within the suburban town of Weston, Massachusetts, this type of coordinated approach has been ongoing for nearly 4 decades. This article describes the integration of forest ecology and management research, including a forest inventory and long-term monitoring program, to educate townspeople about their forests, engage students in ecological research, and provide data that the town can use to make informed management decisions. This article presents a novel model for a research-based community forestry program, results from the first inventory and plot measurement period, and describes how other towns can use this type of program to supplement existing active forest management, or provide a baseline for future management. Results are applicable to municipalities that own forest land, as well as land trusts or other private entities that wish to manage their forests using a community based forestry model.     

Evaluation of maternal parent and puroindoline allele on kernel texture in a reciprocal cross between two hard spring wheat cultivars

Kernel texture is an important characteristic for both the milling and the end-use quality of wheat (Triticum aestivum L.). Gene sequence variation and mutations to the two puroindoline genes (Pina and Pinb), located at the Ha locus on chromosome 5DS, account for the majority of variation in wheat kernel texture. Other factors also influence kernel texture, including effects associated with different maternal parent backgrounds. To investigate the effect of two hard puroindoline alleles in different maternal backgrounds, a population of 228 recombinant inbred lines (RILs) derived from a reciprocal cross between two wheat cultivars ID377s (Pina-D1b/Pinb-D1a) and Klasic (Pina-D1a/Pinb-D1b) were examined in two succeeding generations (F₇ & F₈). Kernel texture was determined using the Single Kernel Characterization System (SKCS) and the RIL puroindoline haplotype was identified by the sequence-specific PCR amplification of each gene. Analysis of variance identified a significant (P 0.001) effect of the maternal parent and puroindoline mutation on kernel texture. RILs containing the Pina-D1b mutation were significantly harder than lines containing the Pinb-D1b mutation. RILs which had Klasic as the maternal parent were significantly harder than those which had ID377s as the maternal parent. When the maternal parent and puroindoline allele were analyzed in combination, RILs derived from Klasic as the maternal parent and the Pina-D1b allele were significantly harder (P 0.001) than those containing the same allele but ID377s as the maternal parent. The same occurred for RILs containing the Pinb-D1b allele, lines with Klasic as the maternal parent were harder than lines with ID377s as the maternal parent. These results corroborate the harder phenotype of the Pina-D1b allele and indicate a significant maternally-inherited contribution to kernel texture variation.     

Analysis of puroindoline a and b sequences from Triticum aestivum cv. `Penawawa' and related diploid taxa

Flanking sequences of the puroindoline a(pinA) and puroindoline b (pinB) genes from Triticum monococcum, T. urartu, Aegilops speltoides and A. tauschii were obtained by inverse PCR. Two accessions from each of these related diploid taxa were sequenced, and the sequences compared to those of the soft hexaploid wheat cultivar `Penawawa'. As expected from the origin of the D-genome in hexaploid wheat, the highest sequence identity was observed for the A. tauschii sequences, whereas the sequences for A.speltoides were the most divergent. The promoter sequences were further analyzed for putative regulatory elements, and the possible significance of several highly conserved sequence motifs is discussed. Western blots of Triton X-114 extracted proteins separated by SDS-PAGE confirmed the accumulation of pinA and pinB gene products in the endosperm of all the germplasm lines studied. The deduced amino acid sequences for the related diploid taxa do not imply any major structural changes as compared to the wild-type T. aestivum puroindolines, and is therefore in agreement with the soft endosperm texture of these species. This revised version was published online in August 2006 with corrections to the Cover Date.     

Comparison of model forms for estimating stem taper and volume in the primary conifer species of the North American Acadian Region

? The performance of ten commonly used taper equations for predicting both stem form and volume in balsam fir [Abies balsamea (L.) Mill], red spruce[Picea rubens (Sarg.)], and white pine[Pinus strobus (L.)] in the Acadian Region of North America was investigated.

? Results show that the Kozak (2004) and Bi (2000) equations were superior to the other equations in predicting diameter inside bark for red spruce and white pine, while the Valentine and Gregoire (2001) equation performed slightly better for balsam fir.

? For stem volume, the Clark et al. (1991) equation provided the best predictions across all species when upper stem diameter measurements were available, while the Kozak (2004) and compatible taper equation of Fang et al. (2000) performed well when those measurements were unavailable.

? The incorporation of crown variables substantially improved stem volume predictions (mean absolute bias reduction of 7–15%; root mean square error reduction of 10–15%) for all three species, but had little impact on stem form predictions.

? The best taper equation reduced the predicted root mean square error by 16, 39, and 45% compared to estimates from the widely used Honer (1965) regional stem volume equations for balsam fir, red spruce, and white pine, respectively.

? When multiple taper equations exist for a certain species, the use of the geometric mean of all predictions is an attractive alternative to selecting the “best” equation.

     

A Comprehensive Genotype and Environment Assessment of Wheat Grain Ash Content in Oregon and Washington: Analysis of Variation

A comprehensive analysis of the variation in wheat grain ash content has not been previously conducted. This study assessed the relative contribution of genotype and environment to variation in ash content, with a particular aim of ascertaining the potential for manipulating the trait using contemporary adapted germplasm. A total of 2,240 samples were drawn from four years of multilocation field plots grown in the wheat production areas of Oregon and Washington states. Genotypes included commercial cultivars and advanced breeding lines of soft and hard winter, and soft and hard spring wheats with red and white kernel color, several soft white club wheats, and one soft white spring waxy wheat cultivar. In addition to ash, protein content, test weight, and Single Kernel Characterization System kernel hardness, weight and size were also measured. In total, 20 separate fully balanced ANOVA results were conducted. Whole model R² values were highly significant, 0.62–0.91. Nineteen of the 20 ANOVA results indicated significant genotype effects, but the effects were not large. In contrast, environment effects were always highly significant with F values often one to two orders of magnitude larger than the genotype F values. The grand mean for all samples was 1.368% ash. For individual data sets, genotype means across environments varied ≈0.1–0.3% ash. The genotypes judged noteworthy because they had the highest least squares mean ash content were OR9900553 and ClearFirst soft white winter, NuHills hard red winter, Waxy‐Pen and Cataldo soft white spring, and WA8010 and Lochsa hard spring wheats. Genotypes with lowest least squares mean ash were Edwin (club) soft white winter, OR2040073H hard red winter, WA7952 soft white spring, and WA8038 hard spring wheats. In conclusion, wheat grain ash is more greatly influenced by crop year and location than by genotype. However, sufficient genotype variation is present to plausibly manipulate this grain trait through traditional plant breeding.     

Metabolic profiling: a new tool in the study of wood formation

In the realm of plant genomics, metabolic profiling has become a valuable tool with which to assess the effect of genetic and/or environmental factors on plant development. This paper reports the first application of metabolic profiling on differentiating xylem tissue of loblolly pine. A protocol is presented for the analysis of loblolly pine xylem tissue. The effects of sample preparation, extraction, and derivatization on the corresponding metabolite profiles and yields have been investigated and are reported. Gas chromatography-mass spectroscopy has been used to quantify >60 polar and lipophilic metabolites from wood-forming tissue. It was possible to assign chemical structures to approximately half of these compounds. Comparison of six loblolly pine genotypes, three high cellulose (50-52%) and three medium (45-48%) cellulose, showed distinct metabolic profiles. Principal component analysis enabled the assignment of metabolic phenotypes using these large data sets. Metabolic phenotype clustering occurred in which the three high-cellulose genotypes were segregated from the medium-cellulose genotypes. These results demonstrate the use of metabolic profiling for the study of wood-forming tissue and as a tool in functional genomics.